Section 319
NONPOINT SOURCE PROGRAM SUCCESS STORY
Oil Field Cleanup and Targeted Control of Invasive Brush Species Reduce
Chloride in the Colorado River
., , ,. i , Excess chloride loading from oil and gas wells, invasive
i/VaterDOaieS improved brush species and natural salt deposits led to high chloride
concentrations in the Colorado River below E.V. Spence Reservoir in Texas. This prompted the Texas
Commission on Environmental Quality (TCEQ) to place four assessment units (collectively referred to as
segment 1426) of the Colorado River below E.V. Spence Reservoir on the state's 2002 Clean Water Act
(CWA) section 303(d) list of impaired waters for failure to meet chloride standards. The TCEQ, Railroad
Commission of Texas and the Texas State Soil and Water Conservation Board (TSSWCB) implemented
several saltwater minimization projects that reduced chloride concentrations in the impaired segment.
Following restoration, TCEQ determined that segment 1426 met the Texas' standard for chloride, and
removed it from the list of impaired waters in 2012.
Problem
The Colorado River below E.V. Spence Reservoir
flows through Coke and Runnels counties in west-
central Texas. The segment begins below E.V.
Spence Reservoir and meanders for over 60 miles
until it reaches O.H. Ivie Reservoir (Figure 1). The
segment contains four assessment units (seg-
ment IDs TX-1426 _ 01 through TX-1426 _ 04). The
watershed is approximately 2,000 square miles and
lies within the Southwestern Tablelands and Central
Great Plains ecoregions. The land is primarily used
for rangeland and agriculture.
Water quality grab samples collected from mul-
tiple stations throughout the segment between
March 3, 1996, and February 6, 2001, showed a
mean chloride concentration of 898 milligrams
per liter (mg/L) for the 2002 assessment period.
This exceeded the site-specific chloride standard
for segment 1426, which requires that the annual
mean chloride concentrations be below 610 mg/L.
On the basis of these data, the state added the four
assessment units comprising segment 1426 to its
list of impaired waters in 2002. Potential nonpoint
sources of chloride in the contributing watershed
included noncompliant oil and gas wells, invasive
brush species and natural salt deposits.
Oil and gas wells produce brine, which, when
improperly contained, can contaminate surface
water. Saltcedar, an invasive brush species, has the
ability to transport salts from groundwater to its
leaves. Surface water salinity increases when the
X West O'Daniel Seep
X Wendkiik Oil Field
X Ballingei Seep
A Beetle Release Sites
I I Saltcedar Application Aieas
O Well Plugging Locations
Abilene
Glasscock
^P
IsH
Runnels
O
°0°°ft
oo0o3
TMDL Watersheds
| 1411-E.V. Spence Reservoir
1426-Colorado-River Below
E.V. Spence Reservoir
Figure 1. Texas' Colorado River segment 1426 (below E.V. Spence
Reservoir) was list as impaired for chloride. Project partners
installed numerous projects—within the drainage areas for both
segment 1426 and segment 1412 (immediately upstream)—to
address the impairment.
leaves are dropped in the fall. In addition, saltcedar
uses excessive amounts of water, which reduces
surface water flow and consequently increases
chloride concentrations.
In 2007 the U.S. Environmental Protection Agency
(USEPA) approved two total maximum daily loads
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(TMDLs) for the segment to address chloride and
total dissolved solids (IDS). TheTMDL load alloca-
tions specified that concentrations of chloride and
IDS released from E.V. Spence Reservoir must
remain at or below 550 mg/L and 1,537 mg/L,
respectively, to allow segment 1426 to meet water
quality standards.
Colorado River below E.V. Spence Reservoir (Segment 1426)
Project Highlights
To better define the sources of chloride and IDS
in segment 1426, the University of Texas' Bureau
of Economic Geology conducted TCEQ-sponsored
ground-based and airborne geophysical surveys
using electromagnetic induction instruments to
delineate the extent and intensity of ground saliniza-
tion and to identify salinity sources. This informa-
tion was used to target implementation projects.
Several management measures to reduce chloride
and TDS levels were defined in the TMDL imple-
mentation plan, including plugging abandoned,
unplugged, noncompliant oil and gas wells; fixing
improperly plugged wells; and conducting targeted
brush control. Between February 2003 and August
2007, 272 wells were plugged in Runnels, Coke,
Nolan, Mitchel, Howard and Scurry counties. Then,
in 2008, a 300-foot recovery trench was installed
in and across the West O'Daniel Seep in Howard
County and wells were plugged in the Ballinger
Seep and the Wendkirk Oil Field in Runnels and
Coke counties, respectively (see Figure 1).
TheTSSWCB implemented a targeted brush control
project to chemically treat saltcedar by aerial appli-
cation of the herbicide Arsenal in a 150-foot corridor
along the Colorado River and its tributaries below
Lake J.B. Thomas to E.V. Spence Reservoir. Through
this effort, a total of 11,391 acres were treated from
2005 through 2007. The estimated life of a one-time
chemical treatment of Arsenal is approximately
15 years.
TheTSSWCB also implemented biological control
of saltcedar by releasing leaf beetles in April 2004
along Beals Creek near Big Spring, Texas, and in
Lake J.B. Thomas. By 2008, the leaf beetles had
defoliated about 140 acres of saltcedar trees. No
beetle damage was seen on any other plants in the
area and the native grasses had recovered after
approximately 2 years.
Figure 2. The average chloride concentration for segment 1426
as determined during Texas' assessment of water quality in
the years 2002, 2006, 2008, 2010 and 2012. Note that segment
1426 was not included in the 2004 assessment.
Results
Chloride concentrations have declined since the
segment was originally identified as impaired in
2002. This downward trend corresponds with the
implementation of the management measures
identified in the TMDL implementation plan. The
average chloride concentration decreased from
898 mg/L in the 2002 assessment to 569 mg/L in
the 2012 assessment (Figure 2). Segment 1426,
which includes four assessment units, now meets
its applicable chloride standard and was removed
from Texas' list of impaired waters in 2012.
Partners and Funding
Funding for the Railroad Commission of Texas'
saltwater minimization projects was provided by
the USEPA through the TCEQ. A total of $2,924,005
in CWA section 319 funds were used; these
funds were matched by $2,177,797 in state funds.
The TSSWCB worked cooperatively with Upper
Colorado Soil and Water Conservation District
(SWCD), Mitchell SWCD, Coke County SWCD,
Colorado River Municipal Water District, Texas
Department of Agriculture, Texas Parks and Wildlife
Department, U.S. Fish and Wildlife Service, Natural
Resource Conservation Service, Texas A&M AgriLife
Extension Service and local landowners to use
$2,307,692 in CWA section 319 funding, matched
with $1,466,166 in state and local funding for the
targeted control of saltcedar.
UJ
(9
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-15-001F
January 2015
For additional information contact:
Tim Cawthon, Texas Commission on Environmental Quality,
Water Quality Planning Division
Tim.Cawthon@tceq.texas.gov • 512-239-0845
Brian Koch, Texas State Soil and Water Conservation Board
bkoch@tsswcb.texas.gov • 979-532-9496
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